1. Field of the Invention
The invention relates to medical implant devices in general and particularly to novel methods of improving the biocompatible properties of medical implants by controlling the electrochemical potential at their surface.
2. Description of Related Art
The use of biomedical implants has revolutionized surgical intervention with an ever-expanding variety of applications in orthopedic, dental medicine as well as in tissue engineering. Despite their clinical success, long-term implantation of medical devices still represents an intrusion on the chemical, physiological and mechanical structure of the human body that can lead to serious complications. In an effort to mitigate adverse reactions, titanium and titanium alloys have been widely adopted as the material of choice for medical implants because of their high strength, inert nature, low weight and outstanding corrosion resistance. Attempts to further improve biocompatibility have focused on the treatment of the surface of the implants with pharmacologically or therapeutically active agents to facilitate tissue repair. For example, orthopedic implants may comprise a range of bone grafting materials, such as demineralized human bone matrix, bovine collagen mineral composites and processed coralline hydroxyapatite, calcium sulphate scaffolds, bioactive glass scaffolds and calcium phosphate scaffolds. The inclusion of osteoinductive materials actively trigger and facilitate bone growth, for example by recruiting and promoting the differentiation of mesenchymal stem cells into osteoblasts.
Despite these improvements, implants remain prone to failure because of sub-optimal integration of the implant into the surrounding tissue, which can lead to peri-implantitis, an acute, subacute or chronic inflammation that continuously affects or opposes the intended implant function. Specifically in critical implant regions, especially with dental implants, the biologic environment and physiologic conditions is a complicating factor with a higher risk of infections due to the microbial, bacterial or fungi flora. Typical effects that may be caused by peri-implantitis of dental implants are inflammation of mucosa, loss of attached gingival, exposure of a cervical portion of the implant and loss of the surrounding bone and functional implant failures. A further significant issue is that the absence of the tooth induces spontaneously alveolar bone remodeling with resulting atrophy. Atrophy may subsequently cause more complex complications for reconstruction.
For the foregoing reasons, there is a continuing need for medical implants that mitigate adverse reactions such as peri-implantitis and bacterial infections at the site of implantation.